I downloaded sons of skyrim cdlc from here and I put it in my dlc folder and everytime I launch the game, it doesn't show in the learn a song list. I have my list sorted with the dlc at the bottom, so I am sure it isnt there. I have a similar problem with Operation Ground and Pound by DragonForce as well.

Please read these tutorials in full:

http://customsforge.com/topic/901-how-to-use-custom-dlcs-in-rs2014/

http://customsforge.com/topic/10000-song-not-showing-up-lets-fix-that/

Most likely the second one will help you, but I always suggest that those new to CDLCs read and implement the first one too (if you haven't already).